diff --git a/src/V3ParseImp.cpp b/src/V3ParseImp.cpp
index f532cacc5..55e9994c9 100644
--- a/src/V3ParseImp.cpp
+++ b/src/V3ParseImp.cpp
@@ -515,6 +515,12 @@ void V3ParseImp::tokenPipelineSym() {
                     token = yaID__ETC;
                 }
             }
+        } else if ((token == yaID__LEX || token == yaID__CC)
+                   && (*(yylval.strp) == "mailbox"  // IEEE-standard class
+                       || *(yylval.strp) == "process"  // IEEE-standard class
+                       || *(yylval.strp) == "semaphore")) {  // IEEE-standard class
+            yylval.scp = NULL;
+            if (token == yaID__LEX) token = yaID__aTYPE;
         } else {  // Not found
             yylval.scp = NULL;
             if (token == yaID__CC) {
diff --git a/test_regress/t/t_mailbox.out b/test_regress/t/t_mailbox.out
new file mode 100644
index 000000000..5a7cc1581
--- /dev/null
+++ b/test_regress/t/t_mailbox.out
@@ -0,0 +1,4 @@
+%Error: t/t_mailbox.v:20:4: Can't find typedef: 'mailbox'
+   20 |    mailbox m;
+      |    ^~~~~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_mailbox.pl b/test_regress/t/t_mailbox.pl
new file mode 100755
index 000000000..b8b56e6f0
--- /dev/null
+++ b/test_regress/t/t_mailbox.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2020 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    fails => $Self->{vlt_all},
+    expect_filename => $Self->{golden_filename},
+    );
+
+#execute(
+#    check_finished => 1,
+#    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_mailbox.v b/test_regress/t/t_mailbox.v
new file mode 100644
index 000000000..21eadf323
--- /dev/null
+++ b/test_regress/t/t_mailbox.v
@@ -0,0 +1,86 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2020 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+// Methods defined by IEEE:
+//  class mailbox #(type T = dynamic_singular_type) ;
+//     function new(int bound = 0);
+//     function int num();
+//     task put( T message);
+//     function int try_put( T message);
+//     task get( ref T message );
+//     function int try_get( ref T message );
+//     task peek( ref T message );
+//     function int try_peek( ref T message );
+//  endclass
+
+module t(/*AUTOARG*/);
+   mailbox m;
+   int     msg;
+   int     out;
+
+   initial begin
+      m = new(4);
+      if (m.num() != 0) $stop;
+      if (m.try_get(msg) > 0) $stop;
+
+      msg = 123;
+      m.put(msg);
+      msg = 0;
+      if (m.num() != 1) $stop;
+      if (m.try_peek(out) <= 0) $stop;
+      if (out != 123) $stop;
+      if (m.num() != 0) $stop;
+      out = 0;
+      if (m.try_peek(out) <= 0) $stop;
+      if (out != 123) $stop;
+      out = 0;
+      if (m.try_get(out) <= 0) $stop;
+      if (out != 123) $stop;
+      if (m.num() != 0) $stop;
+
+      msg = 124;
+      m.put(msg);
+      out = 0;
+      m.get(out);
+      if (out != 124) $stop;
+
+      msg = 125;
+      m.put(msg);
+      m.put(msg);
+      m.try_put(msg);
+      m.try_put(msg);
+      if (m.num() != 4) $stop;
+      if (m.try_put(msg) != 0) $stop;
+      if (m.num() != 4) $stop;
+      m.get(out);
+      m.get(out);
+      m.get(out);
+      m.get(out);
+      if (m.num() != 0) $stop;
+
+      fork
+         begin
+            #10;  // So later then get() starts below
+            msg = 130;
+            m.put(msg);
+            msg = 131;
+            m.put(msg);
+         end
+         begin
+            if (m.try_get(msg) != 0) $stop;
+            out = 0;
+            m.get(out);  // Blocks until put
+            if (out != 130) $stop;
+            out = 0;
+            m.get(out);
+            if (out != 131) $stop;
+         end
+      join
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule
diff --git a/test_regress/t/t_mailbox_parse.pl b/test_regress/t/t_mailbox_parse.pl
new file mode 100755
index 000000000..99f2d36c4
--- /dev/null
+++ b/test_regress/t/t_mailbox_parse.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+top_filename("t_mailbox.v");
+
+lint(
+    verilator_flags2 => ["--debug-exit-parse"],
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_process.out b/test_regress/t/t_process.out
new file mode 100644
index 000000000..c024cca10
--- /dev/null
+++ b/test_regress/t/t_process.out
@@ -0,0 +1,22 @@
+%Error: t/t_process.v:22:4: Can't find typedef: 'process'
+   22 |    process p;
+      |    ^~~~~~~
+%Error: t/t_process.v:26:20: Can't find definition of task/function: 'self'
+   26 |       p = process::self();
+      |                    ^~~~
+%Error: t/t_process.v:27:34: Can't find definition of variable: 'RUNNING'
+   27 |       if (p.status() != process::RUNNING) $stop;
+      |                                  ^~~~~~~
+%Error: t/t_process.v:28:34: Can't find definition of variable: 'WAITING'
+   28 |       if (p.status() == process::WAITING) $stop;
+      |                                  ^~~~~~~
+%Error: t/t_process.v:29:34: Can't find definition of variable: 'SUSPENDED'
+   29 |       if (p.status() == process::SUSPENDED) $stop;
+      |                                  ^~~~~~~~~
+%Error: t/t_process.v:30:34: Can't find definition of variable: 'KILLED'
+   30 |       if (p.status() == process::KILLED) $stop;
+      |                                  ^~~~~~
+%Error: t/t_process.v:31:34: Can't find definition of variable: 'FINISHED'
+   31 |       if (p.status() == process::FINISHED) $stop;
+      |                                  ^~~~~~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_process.pl b/test_regress/t/t_process.pl
new file mode 100755
index 000000000..b8b56e6f0
--- /dev/null
+++ b/test_regress/t/t_process.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2020 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    fails => $Self->{vlt_all},
+    expect_filename => $Self->{golden_filename},
+    );
+
+#execute(
+#    check_finished => 1,
+#    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_process.v b/test_regress/t/t_process.v
new file mode 100644
index 000000000..301cb878b
--- /dev/null
+++ b/test_regress/t/t_process.v
@@ -0,0 +1,43 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2020 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+// Methods defined by IEEE:
+//  class process;
+//     enum state { FINISHED, RUNNING, WAITING, SUSPENDED, KILLED };
+//     static function process self();
+//     function state status();
+//     function void kill();
+//     task await();  // Warn as unsupported (no UVM library use)
+//     function void suspend();  // Warn as unsupported (no UVM library use)
+//     function void resume();  // Warn as unsupported (no UVM library use)
+//     function void srandom( int seed );  // Just ignore?
+//     function string get_randstate();  // Just ignore?
+//     function void set_randstate( string state );  // Just ignore?
+//   endclass
+
+module t(/*AUTOARG*/);
+   process p;
+
+   initial begin
+      if (p != null) $stop;
+      p = process::self();
+      if (p.status() != process::RUNNING) $stop;
+      if (p.status() == process::WAITING) $stop;
+      if (p.status() == process::SUSPENDED) $stop;
+      if (p.status() == process::KILLED) $stop;
+      if (p.status() == process::FINISHED) $stop;
+
+      if (0) p.kill();
+      if (0) p.await();
+      if (0) p.suspend();
+      if (0) p.resume();
+      p.srandom(0);
+      p.set_randstate(p.get_randstate());
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule
diff --git a/test_regress/t/t_process_parse.pl b/test_regress/t/t_process_parse.pl
new file mode 100755
index 000000000..b06c6fba8
--- /dev/null
+++ b/test_regress/t/t_process_parse.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+top_filename("t_process.v");
+
+lint(
+    verilator_flags2 => ["--debug-exit-parse"],
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_semaphore.out b/test_regress/t/t_semaphore.out
new file mode 100644
index 000000000..21345fd35
--- /dev/null
+++ b/test_regress/t/t_semaphore.out
@@ -0,0 +1,4 @@
+%Error: t/t_semaphore.v:17:4: Can't find typedef: 'semaphore'
+   17 |    semaphore s;
+      |    ^~~~~~~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_semaphore.pl b/test_regress/t/t_semaphore.pl
new file mode 100755
index 000000000..b8b56e6f0
--- /dev/null
+++ b/test_regress/t/t_semaphore.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2020 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    fails => $Self->{vlt_all},
+    expect_filename => $Self->{golden_filename},
+    );
+
+#execute(
+#    check_finished => 1,
+#    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_semaphore.v b/test_regress/t/t_semaphore.v
new file mode 100644
index 000000000..322a8541a
--- /dev/null
+++ b/test_regress/t/t_semaphore.v
@@ -0,0 +1,49 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2020 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+// Methods defined by IEEE:
+//  class semaphore;
+//     function new(int keyCount = 0);
+//     function void put(int keyCount = 1);
+//     task get(int keyCount = 1);
+//     function int try_get(int keyCount = 1);
+//  endclass
+
+module t(/*AUTOARG*/);
+   //From UVM:
+   semaphore s;
+   int       msg;
+
+   initial begin
+      s = new(4);
+      if (s.try_get() != 0) $stop;
+
+      s.put();
+      s.get();
+
+      s.put(2);
+      s.get(2);
+
+      s.put(2);
+      if (s.try_get(2) <= 0) $stop;
+
+      fork
+         begin
+            #10;  // So later then get() starts below
+            s.put(1);
+            s.put(1);
+         end
+         begin
+            if (s.try_get(1) != 0) $stop;
+            s.get();  // Blocks until put
+            s.get();
+         end
+      join
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule
diff --git a/test_regress/t/t_semaphore_parse.pl b/test_regress/t/t_semaphore_parse.pl
new file mode 100755
index 000000000..abc1f79f3
--- /dev/null
+++ b/test_regress/t/t_semaphore_parse.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+top_filename("t_semaphore.v");
+
+lint(
+    verilator_flags2 => ["--debug-exit-parse"],
+    );
+
+ok(1);
+1;